. We tested the electrical characteristics of LEDs using the forward ac small signal method based the series and parallel modes, and the experimental results show that there are negative capacitance in most semiconductor LEDs.

• （2）、采用基于并联和串联模式的交流小信号法对半导体发光二极管的正向交流电特性进行了检测，测试结果表明半导体发光二极管中普遍存在着负电容。